Conventionally, there is known an electrostatic atomizer for generating electrically charged water particles by cooling an atomizing electrode to allow moisture in air to be condensed on the atomizing electrode, applying high voltage to the condensate water on the atomizing electrode by a high voltage power circuit and thus electrostatically atomizing the condensate water.
In the electrostatic atomizer, when a starting voltage is applied to the atomizing electrode of the electrostatic atomizer, Coulomb's force acts on the water on the tip portion of the atomizing electrode, so that the level of the water locally swells in the shape of a needle having a pointed leading end (called a “Taylor cone”). Electric charges are concentrated on the leading end of the Taylor cone, and thus become densified, so that electric field intensity and Coulomb's force therearound are increased and the Taylor cone grows. The water around the leading end of Taylor cone receives great energy (repulsive force of the densified charges) and is repeatedly segmented and scattered (called Rayleigh scattering), thereby generating charged water particles of nanometer size.
However, when a voltage is applied to the atomizing electrode from the high voltage power circuit at the time of starting the electrostatic atomizer, rush current flows, so that idle discharge (minus ion discharge) occurs in a state in which the Taylor cone is not formed. To that end, the tip portion of the atomizing electrode is vaporized, worn and deteriorated due to long periodic use, thereby resulting in unstable electrostatic atomization.
Further, it is disclosed in, e.g., Japanese Patent Laid-open Publication No. 2007-21370 that, in the electrostatic atomizer, the output of a discharge voltage is fed back to the high voltage power circuit, thus decreasing the variation in high voltage. However, Japanese Patent Laid-open Publication No. 2007-21370 does not disclose a technology of preventing the deterioration of the atomizing electrode due to the idle discharge at the time of starting the electrostatic atomizer.